Form locator



Nov. 23, 1965 T. HALSTEAD 3,219,308

FORM LOCAIOR Filed July 27, 1964 5 Sheets-Sheet 1 FIG.1

INVENTOR LT. HALSTEAD ATTORNEY Nov. 23, 1965 T. HALSTEAD FORM LOCATOR 5 Sheets-Sheet 2 Filed July 27, 1964 INVENTOR.

L T. HALSTEAD A TTORNEYS Nov. 23, 1965 T. HALSTEAD FORM LO CATOR Filed July 2'7, 1964 5 Sheets-Sheet 3 nni lqzxxif JHWL 1 1N VENTOR.

L. T. HALSTEAD FIGA Nov. 23, 1965 L. T. HALSTEAD FORM LOCATOR Filed July 27, 1964 5 Sheets-Sheet 5 l'l'I'I'I'I'I'I'I'I'I'I'l INVENTOR.

L. T. HALSTEAD BY PM faflwmdfi fm zyhlim ATTORNEY United States Patent 3,219,308 FORM LOCATOR Lotus T. Halstead, L. T. Halstead Company, R0. Box 110, St. Albans, W. Va. Filed July 27, 1964, Ser. No. 385,328 8 Claims. (Cl. 249-205) This invention relates to devices used to accurately locate forms for concrete piers or columns and includes means to rigidly support structures during the pouring of the pier or column when these structures are intended to be embedded in the finished pier or column.

This application is a continuation-in-part of my earlier United States application for Letters Patent entitled Form Cap, filed August 28, 1962, and bearing Serial No. 219,836, now abandoned.

Concrete piers The concrete piers which this invention is designed for are circular, generally a foot or more in diameter and vary from a foot or more to several yards in length. They are poured and formed in previously dug or augered holes in the ground and have the topmost portion protruding above the ground to a predetermined elevation.

Although they are used widely to support structures such as buildings or bridges, the columns will be described further in this specification only in connection with the support of prefabricated assemblies as normally used in substations in the electric utility industry and industrial consumers.

Typically such an assembly or item of equipment will be supported on two or more integral legs. In the base of each leg or at each point of hearing are predrilled holes which receive the tops of anchor bolts. These anchor bolts are previously cast into the concrete piers. Failure to locate these bolts in each pier accurately with respect to one another will require expensive and timeconsuming alteration during the installation of the equipment. Failure to have the tops of the piers all at the same elevation and all level will likewise require timeconsuming shimming and grouting of each leg.

In the past, piers for this purpose have been poured primarily in square or rectangular shape. The forms used to pour these square piers have been made of wood or metal and are erected on the site by the contractors workman. While these square piers have been satisfactory, the cost in materials and labor in building and erecting the forms is much higher than with round piers.

Recently a new method of building round concrete piers has been devised. The method employs disposable laminated paper tubes for forms. These patented tubular forms are sold under the trademark Sonotube.

These new forms and piers produced by them possess many advantages when compared with the square forms. First, the round forms are much cheaper than square forms. Second, the cost of erecting the form is drastically reduced since all that is required is that a tube of the proper length be dropped in place. Third, the amount of concrete required to support a given load is reduced since a round pier of a given diameter will support essentially the same load as a square pier having the same dimension across one side. Fourth, the round pier does not deteriorate as rapidly over the years because it has no corners. Therefore, it does not spall as rapidly due to temperature change and is less susceptible to impact damage. Fifth, only a small fraction of form supports are required with these tubular forms when compared with the supports of the square forms. Lastly, the cost of disassemblying the form and finishing the surface of the round pier is much lower.

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The present invention The use of my form locators enables concrete piers constructed with these flexible round tubular forms to be accurately positioned, to have their tops level and at the proper elevation when poured. It further enables anchor bolts cast in these piers to be precisely located with respect to the center lines of the station.

The invention will be further described in connection with the accompanying drawings in which:

FIG. 1 shows the present form locator in an exploded perspective view together with the paper tube surrounded by wooden supports, the bolt supports containing four anchor bolts and the measuring frame used to accurately position these anchor bolts;

FIG. 2 is a plan view of a set of form locators positioned and secured over a set of tubular forms, with a measuring frame positioned over the top right-hand form locator;

FIG. 3 is an enlarged plan view of one of the form locators shown in FIG. 12, illustrating a bolt support positioned diagonally across the top of the form locator;

FIG. 4 is an enlarged vertical cross-sectional view taken on line 3-3 of FIG. 2;

FIG. 5 is a side elevational view of a diameter'bar used with the form locator to determine the true center of the circular form;

FIG. 6 is a plan view of the measuring frame used with the form locator;

FIG. 7 is a cross-sectional view taken on line 66 of FIG. 6, showing the measuring frame positioned on the form locator;

FIG. 8 is a plan view of a measuring frame adapted to fit on a smaller form locator which has two sets of bolt supports positioned on it; and

FIG. 9 is a side elevational view of the measuring frame, adapter and form locator shown in FIG .8.

As shown in FIG. 1, the form locator 5 is basically a square metal plate with a hole in the center only slightly smaller than the tubular form over which it fits. Surrounding the hole, on the underside of the form locator, is a positioning ring 8.

Although this positioning ring has the appearance of a chamfer strip and does in fact serve the function of a chamfer strip in producing a beveled edge at the top of the concrete pier, this is not its primary purpose. Its primary purposes are, first, to enable the form locator when placed on top of the tubular form to hold this flexible form in its intended circular shape, and second, to enable the form to be accurately moved horizontally to its proper position and then held in that position while concrete is being poured.

In constructing a set of concrete piers utilizing tubular forms and the form locators of the invention, after the desired excavation 1 for the concrete piers and underlying foundation or base is formed in the earth, a grid of vertical wooden stakes 2 are driven into the earth adjacent the excavation. These vertical stakes are located by a workman generally in line with the side of the concrete piers to be formed and a mark is made on each stake at the desired level of the horizontal wooden supports 3 for the form locators. As the top of the finished concrete pier will be flush with the top of the 10- cators, whose bottoms rest on these supports 3, the elevation inscribed on the vertical stake will be the thickness of the form locator below the desired elevation of the finished concrete pier. The horizontal supports 3 are then nailed to the vertical stakes 2 to produce a frame on which my form locator rests.

In larger installations it may be desirable to use metal in the horizontal supports 3 because of the large span and the possibility that wooden supports might sag.

Tubular forms 4 are next placed in the excavation by inserting them into the openings formed by the horizontal wooden supports 3. In practice, there is a space between the tubular form and the sides of the supporting members which the drawings for clarity do not show. After they have been adjusted into their approximate position, the excess. end portion of the tubular form protruding above the horizontal supports is removed. A form locator is then placed loosely over the end of each tubular form.

As best shown in FIG. 4, the form locator is held on top of the tubular form by the action of the positioning ring 8. The positioning ring Which-I use is in the form of a beveled ring with a vertical outer edge whose diameter is substantially the same as the inside diameter of the tubular form. The purpose of this positioning ring is to hold the tube firmly in position with relation to the form locator. It will be immediately apparent that any other shape of positioning ring which holds the tubular form firmly in position will serve the same purpose. The particular shape of my positioning ring allows two additional benefits. First, the inner face of the positioning ring is at approximately 45 to the vertical, forming a suitable chamfered edge of the concrete pier when it is poured. Secondly, the positioning ring being inside the tubular form prevents the wet concrete from going over the edge of the top of the form and weakening it due to the blotting action of the exposed top edge which in turn distends the edge and flares it outwardly.

After each tube has been roughly positioned inside of the horizontal supports with the form locator on top of it, a diameter bar, shown in FIG. 5, is placed on top of the form locator. This diameter bar is used to accurately locate the tubular form in its final position. The diameter bar consists of a flat rod 12 With downwardly extending pins 13 at each end. These pins are designed to fit into a pair of the ring of small holes 11 in the form locator which surround and are concentric with the main opening. The pins and openings are designed so that the pins may be inserted only in diametrically opposite pairs of holes.

When the pins are so inserted, the post 15 at the center of the diameter bar marks accurately the center of the circle of both the form locator and of the tubular form underneath the form locator. Bench mark pins 19, which may be removable, are provided at the top of the post 15 and at various points on the side of the form locator to assist the workman and his helper in accurately positioning the form locator.

A transit located to one side of the'excavation is used to sight the exact desired location of .the form. A helper standing on the support bars slides the form locator until the center of the form locator as defined by post 15 is in the position desired by the workman. The helper then rotates the form about pin 15 until it is also properly aligned. At that point, he permanently fastens the cator to the support bars by nailing it through the holes 21.

When several columns are to be poured in a group, as shown in FIG. 2, the workmen need only accurately position one of the several form locators. After he has done this, the helper may accurately position the other form locators by using spacer bars 17 and 18. These previously made spacer bars have a hole at either end to fit snugly over the post of each of the diameter bars in the group, as shown in FIG. 2. When the four bars 17, which form the sides of the square, and the two bars 18, which form the diagonals, are in place, each of the form locators is accurately positioned.

After each of the form locators is so positioned, each is nailed to the support members 3 underneath it and the spacer bars and diameter bars are removed.

When the form locators have been positioned by the workman and nailed to the supports, cross braces 23 may be attached between the horizontal supports, as shown in FIGS. 1 to 3, to further brace the main supports on long spans.

If there are to be no in-cast structures in the concrete pier, the pier is now ready to be poured in only a fraction of the time required to set up an otherwise equivalent square form for the square pier.

Anchor bolts Assuming there are to be in-cast structures such an anchor bolts, they are next positioned in place. Positioning these anchor bolts accurately is one of the major advantages of my form locator. A conventional method of supporting anchor bolts in all forms at present is to drill holes in an ordinary piece of lumber. These holes will be as nearly as possible the correct distance apart and the wooden bolt support is nailed to the opposing sides of the form. The bolts are then put through the holes and hung from the top by a nut.

The system may seem satisfactory but in fact is seldom so. Several problems arise when concrete is poured with anchor bolts held in such a position.

During the pouring of the concrete, the entire column must be vibrated to assure the proper distribution of the aggregate in the concrete. This vibration agitates the anchor bolts and unless they are restrained, they will tend to rotate. Depending on their direction of rotation, they will either gradually rise above their intended elevation or sink below it.

Likewise, they will tend to be skewed out of plumb and 7 it is impossible once all the concrete has been poured to straighten out a long anchor bolt by twisting the top two or three inches remaining above the surface.

Lastly, the size and position of the wooden bolt support make it impossible to properly finish the top surface of the pier.

Bolt supports Using my system, however, these difiiculties are eliminated. Before the concrete is poured, a pair of support bars 24 for the anchor bolt or bolts 25 are laid across the central opening of the form locator roughly at the desired position of the anchor bolt or bolts in the tubular form. A spacer bar 26 is inserted under each end portion of the support bar 24, which holds these bars and thrust washers 35, as shown in FIG. 4, above the eventual surface of the concrete pier. Preferably a fibrous strip 27 is inserted between each spacer bar 26 and the support bars 24. to absorb the vibrations set up during the pouring of the concrete. Alternatively the spacer bar 26 itself may be constructed of material which absorbs vibration. However, since such materials will tend to compress or deform with continued usage, it is preferable to use a solid spacer bar 26 such as a bar of steel and a fibrous strip 27 as shown.

Clamping bars 28 are placed over the adjacent end portion of the support bar 24, one at each side of the central opening of the form locator. Each clamping bar has an opening 29, preferably a slot, as shown in each end portion. These slots allow bolts 31 to pass through the clamping bar and also through holes 11 of the form locator holding the support bars firmly in a predetermined space. Anchor bolts 25 typically are formed with a hook portion 23 atone end to positively and mechanically secure the bolt in an embedded position in the concrete pier after the mix has set around the bolt. The other end portions 34 of anchor bolts are provided with threads. To attach the bolts to the support bars a thrust washer 35 is first screwed onto the threaded end of each anchor bolt. The: bolt is then passed upwardly between the two support bars; and a fiber washer 36, metal washer 37 and conventional nut 38 are placed on top of the bolt and loosely screwed down to allow the bolt to slide in the channel formed by the support bars 24.

The next step is to accurately locate the bolts with respect to the center of the predrilled monnting holes in the base of the equipment to be supported. Accuracy of approximately one-sixteenth of an inch is suflicient for most purposes and may be achieved on these locators using a simple carpenters rule.

Measuring frame However, it will in most cases be more convenient to use a measuring frame 41 which I have devised since it will accurately locate several bolts simultaneously, The measuring frame, as shown in FIGS. 6 and 7, is a hollow square substantially equal in size and shape to the outer dimension of the form locator. Each side member 42 of the measuring frame has a longitudinally extending channel 43 formed in the outer side thereof which terminates in rounded portions adjacent the corners of the measuring frame providing solid corner portions. A positioning leg 44 at each corner of the measuring frame has an upwardly projecting end portion 45 which is engaged in opening 46 at each corner of the frame, thus removably securing the positioning legs to the measuring frame. Markings 47 are provided on each leg to indicate the distance from the top of the measuring frame, preferably at quarter-inch intervals. A collar 48 is mounted on each leg and may be adjusted and .held in position by set screw 49. The bottom of each leg 51 should preferably be pointed to enable it to more easily slide into openings 52 of the form locator. In this manner, the measuring frame may be placed on the form locator and spaced from it any desired distance.

Generally J-shaped slides 53 are mounted on the sid s 42 of the measuring frame with their shorter legs 54 extending into the channels 43. The longer leg 55 of each J-shaped slide lies on the top surface of the measuring frame and contains an aperture 56. A resilient strand or cord 57 connects pairs of slides on opposing sides of the measuring frame. A set screw 58 is positioned in the top portion of leg 55 and serves to hold the resilient cord in its opening. A further set screw 59 is positioned in the midportion of leg 55 to clamp the measuring frame between it and the lower leg of the slide 54. A bench mark 19 may be provided in set screw 59 to further assist the workman in accurately locating the slides 53 and cords 57.

The top surface of the measuring frame is provided with indicator marks 61, preferably designating the distance in inches from the center of each side 42 of the measuring frame. If desired, indicators 62 also may be provided along the inner side of the measuring frame 41. These indicators show the positioning of cords 57 stretched between pairs of the slides.

When the slides have been set to the proper position called for in the plans, the intersection of the cords will define accurately the proper place for the bolts. The bolts are then moved underneath these cords by sliding the bolts in the channel between the support bars and, if necessary, moving the bolt support bars. When this has been done, all of the nuts holding the support bar assembly and the anchor bolts are tightened, leaving the anchor bolts firmly attache-d in their proper location and the proper distance above the surface of the concrete when it is poured. Having the bolts hung from above the surface and having a clearance below the thrust washer allows workmen to finish the top surface While the concrete is setting.

The measuring frame 41 is then removed from the form locator and the locator and tubular form are ready to receive the concrete. A fourth set of openings 63 may be provided in the form locator to receive legs of a funnel, positively positioning the funnel to direct concrete mix into the openings 6 of the form locator and directly into the tubular form without spilling over the tops of the anchor bolts.

The measuring frame 41 may be modified or adapted to allow it to be used with several dilferent sizes of form locators. This modification is shown in FIG. 8 and includes additional openings 46 along each of opposite sides of the measuring frame. An adapter bar 64 for each size of form locator is used. It contains studs 65 to fit into holes 52 and further extend to the edge of the measuring frame where holes 66 are provided for engagement with the legs 44 of the measuring frame.

The form locator shown in FIGS. 8 and 9 is smaller than the measuring frame. Therefore, it requires the use of a pair of adapter bars 64. However, should the form locator be larger than the measuring frame, no adapter bar would be necessary, and the frame could be fit on the form locator by having the openings 52' moved diagonally inward.

Removing the form After the concrete has been poured and has set sufficiently to support the anchor bolts, the bolt support bars 24 may be removed by unfastening bolts 31 and loosening nut 38. Washers 35, 36 and 37 may then be removed.

All of the bolt support members may, of course, be made a unitary piece of metal with predrilled holes. However, my bolt support design gives greater versatility and when disassembling causes less disturbance to the concrete than a single member which supports the bolts.

When the concrete has fully set, the form locator may be unnailed and removed, the supporting frame itself removed, and the tubular form peeled off of the concrete pier to below the ground level. The concrete pier is then ready to receive its load.

It is to be understood that my form locator can also be advantageously used to support other structures during the concrete pouring operation. It may be used to support the reinforcing bars which are incorporated in most concrete piers, or it may be used to support conduit for wiring extending through the concrete pier or guy wire anchors.

The form locator has been described in connection with a circular tubular form. It will be apparent that my form locator is equally useful with a tubular form of any other shape. The only requirement is that the positioning ring 7 be designed to accurately fit that shape. Likewise, the positioning ring, although shown as a continuous circle, need only extend partially or intermittently around the opening to serve its function of accurately locating and holding the tubular form.

Also, while the form locator has been illustrated as a unitary piece of material, it could be made from two interlocking sections to be placed around an already existing pier or to facilitate forming such a pier around an existing steel beam.

I claim:

1. A form locator for accurately locating the horizontal position of the top of a concrete pier poured in a flexible tubular form, said form locator comprising:

(a) a positioning ring which holds the top of said flexible tubular form in its intended shape,

(b) means to hold said positioning ring in a predetermined location during the pouring of said concrete pier.

(0) means contained on the form locator to determine the center of the positioning ring.

2. A form locator for accurately locating the horizontal and vertical position of the top of a concrete pier poured in a flexible tubular form, said form locator comprising:

(a) a positioning ring which holds the top of said flexible tubular form in its intended shape,

(b) said positioning ring having a surface for sliding engagement with a surface of the tube whereby the positioning ring may be placed over the end of the tube and slid vertically to the correct height,

(c) means to hold said positioning ring in a predetermined location during the pouring of said concrete pier,

(d) means contained on the form locator to determine the center of the positioning ring.

3. A form locator for a form comprising:

(a) a plate adapted to be placed on a form and having a top surface and an undersurface and an opening therethrough,

(b) and a positioning ring carried by the plate adjacent to the undersurface thereof and positioned to bear against the inside of the form,

() means carried by said plate to support an anchor bolt within said opening and depending below said plate,

(d) said means to support the anchor bolt comprising at least one member extending across said opening, and means to clamp the member to said plate,

(e) said means to support the anchor bolt including a spacer bar between each end portion of the member and the top surface of said plate to space said member above the top surface of the plate and in which said means to clamp said member to the plate also clamps the spacer bar to the plate,

(f) a frame substantially larger than said plate, at least one adapter bar, means connecting the adapter bar to said plate, the end portions of the adapter bar extending beyond the periphery of said plate, means cooperating with the adapter bar to position and support the frame above said plate and substantially parallel thereto, and means on said frame to indicate any desired location in said opening.

4. A form locator as set forth in claim 3, including a frame of substantially the same dimensions as said plate, means to position and support the frame above said plate and substantially parallel to said plate, and means on said frame to indicate any desired location in said opening.

5. A form locator as set forth in claim 4, in which said means to position and support the frame above said plate is adjustable to selectively space the frame a predetermined distance from the plate, and in which said means to indicate any desired location in said opening comprises at least one pair of slides attached on opposite sides of said frame, and a strand attached to and extending between said slides.

6. A form locator for a tubular form comprising a plate having a top surface and an undersurface and a centrally located first opening therein, a series of second openings concentric with said first opening in said plate and spaced from and extending around said first opening, a positioningring carried by the plate adjacent the undersurface thereof and between said first and second openings, the outer dimension of the positioning ring being such as to snugly fit within the tubular form, at least one member extending across the said first opening, a spacer bar between each end portion of said member and top surface of said plate, a clamping bar overlying each end portion of said member, and means cooperating with at least one of said second set of openings to clamp said clamping bars and spacer bars to said plate.

7. A form locator as set forth in claim 6, including a vibration-absorbing strip between each of said spacer bars and said member.

8. A form locator as set forth in claim 6, including a right angle parallelogram frame of substantially the same dimensions as said plate, a plurality of legs attached to said frame substantially perpendicular to the plane of said frame, a plurality of first pairs of slides, the slides of each first pair bearing on first opposite outer sides of said frame, a plurality of said pairs of slides, the slides of each second pair bearing on second opposite sides of said frame, a plurality of resilient strands each attached between the slides of each pair and maintaining the pair against opposite outer sides of said frame, an additional set of openings in said plate to receive the legs of said hollow frame and position said frame over said first opening in the plate, and an adjustable collar member of each leg, said collar member bearing on the top surface of said plate and spacing said frame above the top surface of said plate.

References Cited by the Examiner UNITED STATES PATENTS 680,432 8/1901 Haase 25121 1,103,664 7/1914 Draper 25-128 J. SPENCER OVERHOLSER, Primary Examiner.

WILLIAM J. STEPHENSON, Examiner. 

1. A FORM LOCATOR FOR ACCURATELY LOCATING THE HORIZONTAL POSITION OF THE TOP OF A CONCRETE PIER POURED IN A FLEXIBLE TUBULAR FORM, SAID FORM LOCATOR COMPRISING: (A) A POSITIONING RING WHICH HOLDS THE TOP OF SAID FLEXIBLE TUBULAR FORM IN ITS INTENDED SHAPE, (B) MEANS TO HOLD SAID POSITIONING RING IN A PREDETERMINED LOCATION DURING THE POURING OF SAID CONCRETE PIER. (C) MEANS CONTAINED ON THE FORM LOCATOR TO DETERMINE THE CENTER OF THE POSITIONING RING. 